string s = 'hello world'

var l = s as [u8]
l[0] = 110
(l[1], l[2]) = (l[2], l[1])
println(s)
println(l as string)

[u8] l2 = [110, 105, 99, 101]

string s2 = s + ' one piece'

println(s2)

string s3 = s2 + ' ' + l2 as string
println(s3)


// 字符串比较操作
var b = 'hello world' == 'hello world'
println(b) // true
println('hello world' != 'hello world') // false
println('a' < 'b') // true
println('a' > 'b') // false